Activated garnets of rare earth metals and group thirteen elements are used as phosphors in optoelectronic components, for example in light-emitting diodes (LEDs). The elements of group thirteen elements are used depending on the wavelength that is required. Rare earth metal aluminum garnets such as yttrium aluminum garnet (YAG) which are activated with another rare earth element, e.g. cerium or praseodymium or a transition metal such as chromium or manganese are prominent phosphors. Lutetium aluminum garnet (LuAG) doped with cerium, LuAG:Ce or (Lu,Ce)3Al5O12, was reported as a stable green phosphor.
For applications in optoelectronic components, dense and highly transparent ceramic material is desired. Therefore, there is need for phosphors, e.g. garnets, with improved properties.